To revert to Google as your preferred search engine, please do the following.

• In the location bar, type about:config and hit Enter.
• In the filter at the top, type: keyword.URL
• Double click it and remove whatever's in there and replace it with http://www.google.com/search?q=

The URL to add in "keyword.URL" becomes a link in this post, so right click it and choose "Copy Link Location" to copy it to the Windows clipboard. Then hit CTRL+V to paste it. Saves you having to type the whole thing.

To reset your home page, do the following.

• Go to the site you want to set as your homepage.
• Click the orange Firefox button and go to Options | Options | General
• Make sure it says "Show My Homepage" in the first dropdown menu.
• Click the button called "Use Current Pages" to set the homepage to the one you have on the screen.

After you complete the above steps, install this add-on to prevent another search engine from modifying your preferences: https://addons.mozilla.org/en-US/firefox/addon/browserprotect/

Thanks, but my issue is with the search box in the top right of screen - not the default search or homepage. This did not help.

I had to remove entries from the registry to restore firefox to a blank slate.

Try this help page:

https://support.mozilla.com/en-US/kb/Search%20bar#Switching_search_engines

Justern, I have the same problem - I want to change the default search engine in the top right of the toolbar. Did you get a useable answer to your question?